Zero Suit Samus is an alternate form of Samus without her Power Suit, wearing a skintight jumpsuit. In this form, Samus' main weapon is the Paralyzer, a small pistol-like weapon that is only capable of stunning enemies. Although Samus has appeared without her armor in previous Metroid games in a small capacity, the first appearance of Samus in her "Zero Suit" was in Metroid: Zero Mission, which consolidated Samus' appearance and abilities outside the Power Suit. While Zero Suit Samus is a very vulnerable and more stealth-based form in her home series, the Super Smash Bros. series enhances her abilities by giving her an extensive, speedy hand-to-hand moveset similar to Sheik, as well as additional weaponry in the form of a "Plasma Whip" mode for her Paralyzer and, in Super Smash Bros. for Nintendo 3DS / Wii U, rocket-powered "Jet Boots" that resemble high-heeled stilettos.

When Samus finishes her Final Smash, the Zero Laser, the force of the beam is so strong it causes the Power Suit to fall off, allowing Zero Suit Samus to be playable. Zero Suit Samus is more swift and agile than her armored form, though lighter and easier to KO. In this state Samus fights using a gun that can stun opponents and also turn into an energy whip. Zero Suit Samus's neutral special move is the Paralyzer, in which she fires a blast from the gun that can stun opponents. Her side special is Plasma Whip, in which she fires a whip to the side that deals more damage at the tip. Her up special is Plasma Wire, in which she fires the whip directly up. Finally, her down special is Flip Jump, in which she does a jump that can be followed up with a kick. Similar to Samus, Zero Suit Samus's grab also uses the Paralyzer's whip, which gives her an extended grab; this and her up and side specials can all be used as tether recoveries.

At the character selection screen, when players select Samus, they can start the battle as Zero Suit Samus by holding the following buttons when proceeding to the stage selection screen.

Samus first appears in the Subspace Emissary in her Zero Suit, infiltrating the Research Facility to retrieve her stolen Power Suit. Along the way, she finds Pikachu trapped in a power generator and frees it. Eventually, Samus tracks her Power Suit down, but was stopped by evil copies of it. She defeats them and retrieves her suit. She, along with Pikachu, spends most of the Subspace Emmisary in either the The Research Facility or The Subspace Bomb Factory. When Samus is selected on the World Map, she can still be turned into Zero Suit Samus by pressing the grab button.

Zero Suit Samus reappears for Super Smash Bros. for Nintendo 3DS / Wii U as an independent character, after the removal of in-battle transformation moves. Her overall appearance has been somewhat altered, still using her general design from Metroid: Zero Mission while also taking elements from her appearance in Metroid: Other M. As a result of being a separate character, she has a different Final Smash, Gunship, in which she jumps into the gunship. For her general moveset, she adopts different footwear, her boots now featuring a pair of jet boosters on the heels, which enables her kicking moves to be more powerful and have an electricity effect. These jet boots have also replaced her up special move, Plasma Wire, with Boost Kick, which uses the jet heels to boost herself into the air while kicking.

Zero Suit Samus also has two additional alternate costumes, based upon her appearances during the endings for Metroid: Zero Mission and Metroid Fusion.

Zero Suit Samus only appears in the Metroid Big Name Game in WarioWare: D.I.Y.. There is a small chance that Samus appears in her Zero Suit after the player defeats the Metroids on-screen, rather than her in her Power Suit.

Samus can also appear without her armor at random in the Metroid microgame in the earlier WarioWare: Touched!, though she uses her sprite from the original Metroid rather wearing than the Zero Suit.

Zero Suit Samus appears as a Costume Mario costume in Super Mario Maker. Her sound effects are taken from Metroid: Zero Mission; the theme that plays when the game is loaded plays when the Mystery Mushroom is collected, the theme that plays when an item is obtained plays when the level is completed, and the death sound is played when the player loses a life with the costume on.

Samus Aran without her mighty Power Suit. In this condition, she does not have the firepower she's famed for but is in full possession of the agility and athleticism she gained through her childhood training with the Chozo. Without the armor, she's also much, much faster. The weapon she carries is a self-protection device known as a Paralyzer that stops enemies cold.

NA:Samus is far from helpless when her Power Suit is deactivated. Sure, she loses a lot of the moves and weapons she had access to before, but her Jet Boots pick up the slack! She also has the Paralyzer, a versatile weapon that can shock her rivals or change into a Plasma Whip to grab edges and enemies.

PAL:Without her Power Suit, Samus Aran may not have her usual strength, specials moves or over-powered arm cannon, but her Jet Boots definitely kick things up a notch in their own way. The Paralyzer, her gun, does just what you'd expect it to, but it can also turn into a whip for attacking and grabbing onto edges while falling.

(Wii U)

Zero Suit Samus (Alt.)

(3DS)

GBA Metroid: Zero Mission (02/2004)Wii Metroid: Other M (08/2010)

NA:Zero Suit Samus's up special Boost Kick involves a series of fast kicks that end with a swift, sideways-launching one. A perfectly executed attack will hit eight times! Her down special Flip Jump can bury a grounded fighter in the dirt. She can kick midflip by pressing the special button.

PAL:Zero Suit Samus's Boost Kick up special finishes with a swift sideways kick. If you start the move close to an opponent, you can hit them up to eight times and launch them sideways! Her main down special, Flip Jump, buries opponents if you land on them at the end of it. Alternatively, press the button again mid-flip for a drop kick.

(Wii U)

Gunship (Zero Suit Samus)

N/A

NASamus's spaceship carries her through space and serves as her base of operations during her mission. Zero Suit Samus will call down and board her Gunship with her Final Smash. Once she's in the pilot's seat, she has a short time to unleash up to five powerful shots from the ship's weapons. Foes aren't safe even hiding off-screen!

Samus is far from helpless when her Power Suit is deactivated. With her Zero Suit, she doesn't have the firepower she's famed for but is in full possession of the agility and athleticism she gained through her childhood training with the Chozo. Without the armor, she's also much, much faster. The weapon she carries is a self-protection device known as a Paralyzer that stops enemies cold.